For 10 years it's easy - pay a few dozen people to make sure it happens. 100 years is harder, but doable with the same fashion. For a movie example, consider the Western Union message that Doc Brown sent in 1885 to Marty McFly in 1955, in Back to the Future II. Brown had the advantage of knowing that Western Union would exist, but I can imagine similar systems working.

After all, there are long-running experiments which take more than a lifetime, like Beal's germination experiment which started in 1879 and is expected to end in 2100. With enough money you can set up a fund, with a requirement that the information be published at set times in the future.

For 1,000 years? Forget about it. There are few human systems which have worked for that long, and your best bet is to write a document that's interesting enough so as to inspire someone in the future to transmit that document for you. For example, read http://www.theatlantic.com/past/docs/issues/97nov/teller.htm and see how someone in 1916 convinced someone in 1997 to do something.

For an entertaining fable, read http://www.centauri-dreams.org/?p=11894 regarding a tale of New College, Oxford needing new oak beams.

The winner's efforts show the difficulty in designing something that will last, and be recognizable, in thousands of years. It was constructed of titanium and glass, the instructions were custom pictographs, and the location where it was placed was carefully orchestrated.

This illustrates the problem with trying to span such a long time. What will the world even look like in 100 years, let alone a millennium? Will we have the Internet? Will we speak any recognizable language? Heck, will we live in this solar system?

Although this idea is quite stupid owing to extremely large possibility of the cult dying out, its protected from decay of devices and protocols with time.

-http://longnow.org/clock/ -https://en.wikipedia.org/wiki/Long_Now_Foundation